95 .HEATER/DEFROSTER NOT WORKING. DASHLIGHTS FLICKER

1995 Honda Accord

95 Accord EX. Approx 135k miles. I have a few issues that may or not be related. My heater and defroster do not blow any warm air. The car was in Hawaii for 3 years so the heater wasn't used. The a/c will blow cold air most of the time. I've broken two temp knobs on the dash by turning them too far causing them to break from the inside. The other issue I am having is my dash lights flicker on and off. They stay off most of the time unless I hold the dimmer switch all the way to the left. My temp gauge and odometer/speedometer stopped working, but my tachometer and gas gauge still work. I wasn't sure if all of this could be related to something electrical in the dash. Thanks for any help you can provide.